<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta http-equiv="X-UA-Compatible" content="IE=edge">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>Document</title>
    <style>
        div{
            display: flex;
            width: 80%;
            height: 300px;
            background-color: pink;

            /* 1.设置主轴的方向：子元素在主轴上排列 */
            
            /* 默认从左到右 */
            /* flex-direction: row; */
            /* 从右到左 */
            /* flex-direction: row-reverse; */
            /* 从上到下 */
            /* flex-direction: column; */
            /* 从下道上 */
            flex-direction: column-reverse;
        }
        div span{
            width: 150px;
            height: 50px;
            background-color: skyblue;
            margin: 5px;
        }
    </style>
</head>
<body>
    <div>
        <span></span>
        <span></span>
        <span></span>
    </div>
</body>
</html>